This thesis gives an overview of the diseases that occur during the cultivation of pearl oysters, as well as the method of disease control and health status monitoring. Pearl oysters belong to the family Pteriidae, and the process of commercial culture is called pearl farming. The most important commercial species are the Akoya pearl oyster Pinctada fucata, the golden or silvernosed pearl oyster P. maxima and the black-lipped pearl oyster P. margaritifera. Most diseases occur when an opportunistic pathogen enters cultivated population where individuals are exposed to greater stress than in nature, most often because of stress due to handling and overcrowded conditions. Pearl oysters can be affected by various infectious diseases caused by viruses, bacteria and protists, which are responsible for outbreaks of mortality and have a significant commercial impact. The main cause of pearl oyster mortality are viruses from the Herpesviridae and Iridoviridae, while the most common bacterial pathogens are species of the genus Vibrio. To a lesser extent, diseases are caused by fungi, sponges of the genus Cliona, flukes, tapeworms and nematodes. Good aquaculture practice, constant health monitoring and the development of reliable diagnostic tools are of the most importance for disease prevention and control.